According to research carried out by academics at Penn State University, Pennsylvania, people who slept for six hours a night had significantly more concentrated urine and were more dehydrated compared to those who regularly slept eight hours a night, which is the recommended amount.

The study, published in the journal SLEEP, involved more than 20,000 adults in the US and China, all of whom had their sleeping habits and urine samples analysed.

The authors concluded that the links between sleep quality and hydration are down to a hormone in the body called vasopressin.

"Vasopressin is released both more quickly and later on in the sleep cycle," explains lead author Asher Rosinger, who is an assistant professor at Penn State.

"So, if you're waking up earlier, you might miss that window in which more of the hormone is released, causing a disruption in the body's hydration.

"If you are only getting six hours of sleep a night, it can affect your hydration status.

"This study suggests that if you're not getting enough sleep, and you feel bad or tired the next day, drink extra water."

Dehydration can have a number of adverse effects on the body, such as dizziness, feeling drowsy and having dark-coloured, strong-smelling urine.

The most obvious way to stay hydrated is to drink plenty of fluids throughout the day and avoid or limit drinks such as caffeine, tea and alcohol, which can dehydrate the body.

But when it comes to how much water one should drink each day, the advice is conflicting, with some experts suggesting as much as four litres while others say two.

A recent study revealed that half of Britons have no idea how much water they should be drinking daily, while a third admitted they fail to keep themselves properly hydrated and don’t drink water unless it’s mixed with something else.

The survey, carried out by British Summer Fruits and undertaken by 2,000 people, also found that 23 per cent of respondents would choose to stay hydrated by drinking soft fizzy drinks.

“There are many healthy and delicious ways to beat dehydration,” a public health nutritionist commented at the time.